Staff Correspondent:The death toll from heavy rains in Brazil’s southern Rio Grande do Sul state has climbed to 37, with at least 74 people missing, according to the state’s civil defence agency.

The authorities in Rio Grande do Sul have declared a state of emergency as rescuers continue to search for dozens of people reported missing among the ruins of collapsed homes, bridges and roads.

Rescuers and soldiers have been scrambling to free families trapped in their homes, many stranded on rooftops to escape rising waters.

Storm damage has affected nearly 150 municipalities in the state, also injuring 36 people and displacing more than 10,000.

Governor Eduardo Leite said Rio Grande do Sul was dealing with “the worst disaster in [its] history”, adding that the number of dead was expected to rise.

On Thursday, Brazilian President Luiz Inacio Lula da Silva promised “there will be no lack of human or material resources” to “minimize the suffering this extreme event … is causing in the state”.